1. Field of the Invention
The present invention relates to a door-lock control device for vehicle, e.g., a door-lock control device for an automobile serving as a typical vehicle.
2. Description of the Related Art
Conventionally, in an automobile serving as a typical vehicle, there is provided a locking system having a so-called lock-keep system in which a locked state is set when a door of the automobile is closed, and the locked state is kept.
As an example of such a locking system, Japanese Patent Publication Laid-open No. 58-176374 proposes a so-called 2-motor-3-relay-type locking system. In the system of this type, a transition to the states, i.e., a locked state, an unlocked state, and a lock-keep state is realized by a control unit constituted by two motors and three relays.
However, in the prior art described above, the control unit turns two of the three relays on/off at the same timing. If the timings of the two relays are shifted from each other for some reason, a transition to a state different from a state desired by an operator (i.e., state selected by the operator) may be made. In particular, an unexpected transition to the lock-keep state has a problem in safety.